Hexar AF - Rom access and colimation settings

Hi,

 

This is my very first message here so i'll try to make it short and understandable. (Sry for my english, im french)

 

Little pre story :

I've had a dead Hexar AF for a while now waiting for a saving attempt. The bottom circuit around the two 10V capacitors had corroded tracks that were beyond repair. Lately, i've found a donor for the circuit so i transfer the main PCB from one camera to another.

 

http://tiboalberny.com/wp-content/uploads/2018/05/IMG_20180425_164437-1707x1280.jpg

 

After completing the soldering and reassembling, the camera turns on and pretty much works.

 

Not the AF function thought.

Manual focusing works, the lense moves.

 

Collimation values can be reset directly in the software by accessing the ROM of the camera. Here's an excellent article (link) that shows how to access the ROM and giving a lot of informations about it.

To summarize it quickly, ROM access can show you how the autofocusing is set for the different distances of the lense (0,6m for exemple ) and then you can compare it with the values given by the sensor in real time if you focus at the given distance. Please read the article. And then adjust if you feel the need.

 

My problem is that inside the ROM, i can see the setting stored but the sensor live reading stays at 000 .

Im wondering if the sensors are dead (not really realistic unless i damaged it with the soldering). I am thinking about transferring the sensors from the donor camera or maybe the chip containing the ROM

 

The article is talking about conversations on this forum that are 15 years old now. I'm hoping some of the guys are still here .

 

Any ideas or help really appreciated.

Thanks :)

Wouldn't it have been far easier to just jumper the corroded tracks with some fine wire?

Wouldn't it have been far easier to just jumper the corroded tracks with some fine wire?

I would have prefer that solution of course, but it was not an option. Batterly leakage, plenty of tracks are dead on both sides of the PCB and capacitors busted...

Check the flexible PCB connectors. IME those ribbon connectors only stand up to one or two disconnect/connect sequences before becoming extremely unreliable. A spray of contact cleaner might help.

 

Also check that the version numbers of the boards you've swapped are identical. Makers sometimes update boards and make minor track route changes or swap chips for cheaper/more available ones.

After messing for the ROM a little too much and without interacting with the circuit, the screen will only display B.C. now. I removed the battery for 24h to be able to revive it just for a little while before BC comes up again. New battery is not helping.

I've then checked the PCB and could not find anything wrong with it. I've got continuity along the circuit, got the right voltage on the 2 motor drives on the bottom and the one on the front left. I cannot find a datasheet for the main Mitsubishi microcontroller , probably too old...

 

The version of this chip is different on the 2 boards but it should be a minor version as it's only the last number before the FP (1 on the old, and 2 ont his one)

 

http://tiboalberny.com/wp-content/uploads/2018/05/IMG_20180504_221552-e1525688231154.jpg

As expensive as these cameras are (why??), they're still limited by taking rubbishy 35mm film.

 

Is it worth wasting your valuable time trying to resurrect one, when it obviously wants to stay dead?

 

Stick the undoubtedly excellent lens on a Sony Alpha6000 or similar, see what the lens is really capable of, and move on!